The parallelism system for power transformers equipped with shunt taps under load has traditionally been done by an electro-mechanic panel, with analog indication of TAP position and manual tap change.…
The inspection, maintenance and safety procedures promoted by NR10 at Braskem’s PP04 plant brought the opportunity of improving processes and using new technologies for keeping the productive continuity. As rule in the group, each 03 years the manufacturing unit is interrupted and a general inspection is made in the main components, from the structures, machines and up to the power substation.
Since it represents one of the most important and profitable plants of the group, PP04 cannot run the risk of interrupting its production as bad as the operative conditions or power interruption seems. In this sense, through the maintenance engineering, a pioneer work has started for the industrial sector with regards to the cares with power transformer.
The electric power is one the essential inputs for the Propylene production, and its absence may bring losses of at least 10 days of production line interruption. Substation PP04 counts on a single 88 kV / 13.8 kV transformer of 20 MVA and this one is in charge of supplying to the entire plant. Thus, in addition to the conventional maintenance procedures in all high voltage equipment (fuses and circuit breakers, CTs and PTs, insulator, etc.), as preventive tests, online monitoring technology was added in order to diagnose and prognosticate the operative status of the power transformer.
In order to maintain the profitability with the production, the technical initiative increases the safety of the collaborators, reaches the higher performance of the assets and obtains the uninterrupted supplying of electricity for meeting constant productive growth.
Technology in favor of plastics production
In April 2011, during the NR10 interruption for inspection and maintenance of the PP04 plant’s boilers, one of Braskem’s units in Mauá, in partnership with Treetech Systemas Digitais, performed the implantation of the online monitoring system for a full management of the substation’s power transformer.
By initiative of Reliability Engineer José Rafael do Santos, interested in guaranteeing the electric supplying of the pant, they sought Treetech’ solution in order to improve the quality of the system itself (increase the asset operation reliability) and make the maintenance work more assertive and intelligent.
Based on Treetech’ Sigma4net™ specialist software’s engineering models, which through IEDs smart sensors monitored the main electric, mechanical and chemical variables of the transformer, Braskem now counts on the ideal maintenance tool for getting reliable information for helping in the decision making. In real time, it is possible following-up the operation status of the electric machine and then, foreseeing possible supplying faults and interruption.
The designed system contemplates the full monitoring of the capacitance graded bushings, removal and replacement of ancient analogical thermometers by the digital temperature monitor, automatic voltage regulation and overcharge switch monitoring, besides the online follow-up of (H2) gas and moisture dissolved in insulating oil.
All the data obtained by the sensors directly installed in the transformer are sent to the server located in Braskem own plant and, after processed, they will be made available online at the computer screen. Through the intranet, it is possible accessing the system from any authorized terminal.
“With the new tool, Braskem is able to follow-up the operation of the transformer and then planning better the maintenance actions such as corrective and preventive interventions. In this scenario, we also have conditions of assessing future investments and assuring that the plant keeps breaking production records”, asserts Eng. José Rafael dos Santos, person in charge of the implementation of the new system.
“The work performed met all the safety standards of Braskem and made the transformer’s operation safer and more reliable. The entire team is aware on the importance of the work and it has already contributed so that there are no electric problems in the plant.”, highlights José Montinho, Treetech’s application engineer.
Braskem group shows that it is always seeking the improvement of the processes and that the initiatives for increasing the reliability brings expressive results with regards to the production and profitability.
With the use of the Sigma, Mauá’s PP04 unit performs:
- Online diagnosis of the transformer’ status;
- Visualization of alarms and warnings and action according to the rules and procedures applicable to the regular and contingent operation conditions;
- Maintenance, operation and planning actions;
- Standardization of the actions and communication in the maintenance area;
- Identification of assets efficiency optimization opportunities;
- Effective management of the maintenance through periodical reports of performance and assets status.
The list of equipment and solutions which are part of the transformer TR1 (20 MVA) of 88 kV from SE PP04 of Mauá, is presented below:
- TM1 – Temperature Monitor
- BM (Bushings Monitor) for AT
- AVR – Voltage Regulation Relay
- IDM – OLTC Torque Monitor
- GMP – Gas and Humidity Monitor
- Software Sigma4net™
- Full training for use and operation of the system.